Re: [PATCH] drm/i915: Add aub debug support for kernel

[Chris Wilson <chris@chris-wilson.co.uk>]

On Tue,  2 Nov 2010 17:11:36 +0800, Yuanhan Liu <yuanhan.liu@intel.com> wrote:
> The AUB file is a file format used by Intel's internal simulation
> and other validation tools. The content of an aub file is a subset
> collection of all the data needed by GPU.
> 
> Here now just collects the data that are going to be written into
> register, since the others data like ring buffer, buffer objects
> are dumped at user space by libdrm.
> 
> The currentl implementation: hooks the I915_WRITEx macro. The basic
> idea is write down all the reg offset and reg val before writing
> them to register.

This part looks possible to achieve just using tracepoints (and replace
the current debug printk in the process). The advantage of that is we
can then tap into a low overhead tracing mechanism with a *ringbuffer*!
;-) It will require a bit of userspace scripting to do the .aub format
conversion.

I presume the plan will be to include batchbuffer+auxiliary buffer
contents as well in order to capture the complete temporal sequence for
debugging+replay?

Being able to trace the register writes using ftrace is good... In fact we
can remove our own printks and just use mmiotrace. So is it possible to
post-process mmiotrace into .aub?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre